Model 95 XP 486 System Board

Model 95 XP486 Technical Reference 

SHS15F2246     IBM PS/2 Model 95 XP 486 HMR
SHS85F1676     IBM PS/2 Model 95 XP 486 HMS
 

BH1 Battery 
F1 Keyboard Fuse 
J1, J2, J5, J6, J9, J11 32 bit slot 
J3 Operator Panel
J4 Unknown 
J7 Floppy Controller
J8 Base Video Extension slot 
J10 Auxiliary Video Extension slot 
J12 Complex slot 
J14 Parallel
J16 JMP1
J17 Serial
J26 Mouse
J27 Keyboard		 J28 Side Cover Fan
U7 24.0000 MHz Osc 
U12 N82077AA 
U18 33F5499 
U22 SRM2264LC12 
U24 20.00000 MHz Osc 
U25 14.3181 MHz 
U26 85F0464 
U27 64F0942 
U30 Dallas DS1210 
U32 Dallas DS1285 
U33 22.1184 MHz Osc 
Y1 32.768 KHz Crystal

DS1210 Nonvolatile Controller Chip - Converts CMOS RAMs into nonvolatile memories
Dallas DS1285 Real Time Clock  Datasheet [1 page]
DS1285 DS1285 '93  [4 pages]
DS1287 Datasheet [used to describe D1285 pins, 17 pages]

SRM2264LC12 Datasheet  Standard SRAM, 8KX8, 120ns, CMOS, PDIP28

BH1 - Common CR2032 Lithium coin cell with a normal life expectancy of five to seven years. Battery life is directly related to how much the machine is used, since the battery is used only when the system is powered off.   For correct machine operation, battery voltage should be between 2.5 volts and 3.7 volts. NOTE: Low voltages can corrupt CMOS bits.
 
     To check the battery voltage:

        - Turn Off System Unit Power
        - Remove Battery From Battery Holder.
        - Check Battery For Voltage Of 2.5V - 3.7V DC.


     If battery voltage drops below 2.5 volts, replaced it with a CR2032.
 
  After replacing battery, power on, check configuration, and check for proper operation.

SIMM Connector Versions [Grey or Green]  
8MB ECC SIMMs from IBM (Option P/N 92G7208, FRU P/N 92F0098) may not fit properly in the SIMM connectors of some systems.

     The following system types and models are potentially affected.
        8595 - All models
        9595 - model 0LF   (See note below)

Early production 8595 system boards have gray plastic SIMM connectors which physically interfere with the installation of the referenced 8MB ECC SIMM.

Later production system boards used a green SIMM connector, which is compatible with the larger SIMMs. Many earlier systems, which have been serviced in the past 18 months, could have the later production system board (green SIMM connectors) already installed.

All system boards with green memory SIMM connectors, regardless of model number or processor upgrade are not affected.

NOTE:  9595 model 0LF is the only model of 9595 to use the 8595 system board, FRU P/N 92F0270, (identified by a single serial and a single parallel port).

8595/9595 Ports
 
8595 / 9595 Ports

LPT is standard parallel port 
COM DB25 serial port capable of 345K 

 
8595 / 9595 Operator Panel
   On the earliest 8595s, the power button has no shutter and is surrounded by a raised lip. On later models, the power button is covered with a shutter.

DB25 Serial Port


DB25 Serial Port Pinout

Pin

Signal

Pin

Signal

1

N/C

14

N/C

2

Transmit Data

15

N/C

3

Receive Data

16

N/C

4

Request To Send

17

N/C

5

Clear To Send

18

N/C

6

Data Set Ready

19

N/C

7

Signal Ground

20

Data Terminal Ready

8

Data Carrier Detect

21

N/C

9

N/C

22

Ring Indicator

10

N/C

23

N/C

11

N/C

24

N/C

12

Reserved

25

N/C

13

N/C

0

0


8595 / 9595 Parallel Port 




J4 There is no official name, but... 

Jim Shorney
   During my LED adventures poking around a bad 95 planar, I decided to investigate the mysterious J4, since it's right next to the operator panel connector anyway.  Seems it was an easy target.  The outer two pins are connected to ground.  The center pin is tied to operator panel connector pin 29 "-Remote power-on request". 

Jim, I followed that pin out a while back. So it goes to remote power on. OK. What, praytell, is the importance of your find? 

Tim Clarke
    Well, doesn't it sound as though he's determined that J4 is the "Wake-On..." header? So, do you just apply 5V for electronic-triggered power-on? 

Um, hadn't thought of that... 


The parallel port is NOT ExpressPrint capable... 

From the Godfather-
   Seriously: the 8595 planar is stage 3 and does not support the stage 4 "synchrostream mode", which is turned off then. It supports the normal 64-bits burst mode with up to 40MB/s. So a Type 4 platform will be significantly slower in an old 8595-type planar than in a Server 95A planar (the one with the two serial and two parallel ports). The planar controller on the "single-LPT" planars does not return the proper values on trying to start up the Synchro-Stream - therefore it is not used. The only advantage left over is the faster CPU and higher calculation data throughput - and the ability to run Pentium software (if required). The overall performance is of course higher compared with e.g. the DX-50 platform - but it does not even come close to the values achieved with the same processor card in the 9595A "double LPT"-planar. At least not in a cumulative / weighted application which includes combined calculation and I/O traffic loads. 

   For information again: The "small" 9595s model -xLx (Type 2) and -xMx (Type 3) had the old planar - all others usually had the 9595A-planar (Type 4 -xNx, -xPx, -xQx). 

Editor's Note: Checked a -xKx and -xMx planar. Same chipset, same oscillator values. Only difference was some SMD oscillators replaced metal ones. A few less logic chips. And the -xLx, -xMx planars are a lovely green. 

9595 Main Page